It's not that easy, Greg. IF you can suggest a method.
I looked under Mountain Dulcimer, and got lots of hits. Too many to check each and every hit for Croydon/Crawley. I tried Crawley, and I tried Croydon, and none come up with Dulcimers in the subject. Short of reading EACH and every thread which mentions Mountain Dulcimers, I can't see any way of cutting the time spent. So... if you have some insights into searches that I don't have, please be more specific.